TheBitterEnd
Well-known member
Volcanic Bombs - that's a new one on me; but like I said there are probably more theories than actual chert nodules.
The silica is derived from sponge spicules and micro organisms with silica skeletons (radiolarians) which has been remobilised post sedimentaion. The chert itself is crypto crystalline silica. The nodules form layers that are not bedding related and are therefore post sedimentation. The nodules may center on fossils, burrows, or just randomly. The shapes can also form pseudo fossils.Glenn said:Sorry if this has already been described, and I missed it, or did not understand, but what are the "chert nodules" that you see in limestone.
Thanks in advance.
Brains said:500g of silica sponge spicules...
Brains said:The silica is derived from sponge spicules and micro organisms with silica skeletons (radiolarians) which has been remobilised post sedimentaion. The chert itself is crypto crystalline silica. The nodules form layers that are not bedding related and are therefore post sedimentation. The nodules may center on fossils, burrows, or just randomly. The shapes can also form pseudo fossils...